Critical Review Discussion:Multipollutant Air Quality Management

Where’s the Beef?

John G. Watson (john.watson@dri.edu)

Desert Research Institute, Reno, NV

Presented at:

Air and Waste Management AssociationAnnual Meeting

Calgary, ABJune 24, 2010

Review makes some good points• Effects of different pollutants may not add linearly

• Effectiveness of emission reductions (accountability) can be assessed at emissions, ambient concentrations, exposure, and effects

• Benefits would accrue with more attention to multi-pollutant planning

• Progress has been made as indicated by long-term trends

• PM and O3 strategies are inherently multipullant

• Current practices allow for, and indeed apply, multipollutant AQM

But it doesn’t give us much guidance on how to get from where we are to were we want to be

• The approach is “hypothetical” but not practical

• As proposed, it is based too much on a nebulous “risk assessment” that is not critically evaluated

• Examples are isolated and do not illustrate the iterative AQM process outlined by Bachmann (2007)

NARSTO Review Panel Conclusion• The peer review team commends NARSTO and the assessment

authors for undertaking this assessment, particularly in light of the challenges it posed.

• However, the assessment does not meet its primary objective.• This assessment, while noble in its attempt, tries to accomplish too

broad a scope. • The NARSTO Multi-pollutant Assessment, while attempting to

address the steps required to transition to a multi-pollutant air quality system, does not acknowledge the extent to which a multi-pollutant air quality management system exists at present and what may be needed is an assessment that describes the pre-decision (standard setting) process that involves setting priorities among multi-pollutant risks and controls.

• Accountability, the formal iterative process for evaluating the effectiveness of air quality management actions in meeting air quality objectives gets lost in the various multi-pollutant system arguments.

NARSTO Review Panel Conclusion• The peer review team commends NARSTO and the assessment

authors for undertaking this assessment, particularly in light of the challenges it posed.

• However, the assessment does not meet its primary objective.• This assessment, while noble in its attempt, tries to accomplish too

broad a scope. • The NARSTO Multi-pollutant Assessment, while attempting to

address the steps required to transition to a multi-pollutant air quality system, does not acknowledge the extent to which a multi-pollutant air quality management system exists at present and what may be needed is an assessment that describes the pre-decision (standard setting) process that involves setting priorities among multi-pollutant risks and controls.

• Accountability, the formal iterative process for evaluating the effectiveness of air quality management actions in meeting air quality objectives gets lost in the various multi-pollutant system arguments.

Better example is regional haze

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2005 2015 2025 2035 2045 2055 2065

Year

Vis

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Great Smoky Denali

Baseline

Natural Visibility

• Caused by multiple pollutants, varies by location

• Dose response relationships are known

• Direct and observable relationship between emissions, concentrations, and visual effect

• Accountability is built into the AQM system

• Co-benefits are being evaluated

What are some practical improvements?

• Make emissions certification testing more multipollutant and more consistent with ambient air

• Combine monitors into more compact systems

• Consider the effects of PM reductions in the O3 SIP, and vice versa

• Scan and archive the SIPs and supporting documents so that they can be re-evaluated ten years later

• Consider regional haze, urban haze, and global warming together

Our current AQM system is closer to multipollutant/multieffect than implied by the review

Single Primary Pollutant (e.g. CO)

Single Effect (e.g., carboxyhemoglobin))

Single SecondaryPollutant (e.g. O3)

Single Effect (e.g., pine needle mottling)

Single Pollutant (e.g., PM)

Multiple effects (e.g., morbidity, visibility, ecosystem, material damage)

Multi-Pollutant (e.g. PM, NOx, VOC3)

Single Effect (e.g., respiratory disease)

Multi-Pollutant (e.g. PM, NOx, SO2, GHG, VOC)

Multi-effects(e.g.health, visibility, climate, ecosystem, material damage)

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Christine Loh’s Questions

• Do you know where you are?• How many ways can you leap?• Do you know where you want to

land?• Who has gone before you• Are you keeping track of your leap?• What’s your capacity to leap?• Is everyone leaping?• Why is leaping so hard?